European patents EP-0 390 684 and EP-0 911 051, for example, disclose a tubular respiratory assistance device which forms a main channel and which is designed to be connected via its distal end to an airway of a patient, such that said main channel connects the respiratory system of said patient to the outside, said device comprising auxiliary channels that are connected to deflecting means for injecting convergent jets of respiratory gas deflected toward the inside of said main channel.
A respiratory assistance device of this kind is used particularly on patients whose spontaneous respiration is insufficient, said deflected jets of respiratory gas allowing said patients to be ventilated. In this case, the flow rate of respiratory gas used is a maximum of 0.5 liter per minute for children and 5 liters per minute for adults.
Experience has shown that this known respiratory assistance device could be used as an artificial respiration device on patients suffering from hypoxemia or anoxemia, provided that the flow rate of respiratory gas is greatly increased, for example to 5 liters per minute for children and to 50 liters per minute for adults.
With such high flow rates of respiratory gas, however, it is difficult to ensure patient safety against excessive dilation (and even bursting) of the airways in the event of accidental occlusion of the proximal end of said main channel.